We report the discovery of a new ultra-bright submillimeter galaxy (SMG) behind the Small Magellanic Cloud (SMC). This SMG is detected as a 43.3 ± 8.4 mJy point source (MM J01071−7302, hereafter MMJ0107) in the 1.1 mm continuum survey of the SMC by AzTEC on the ASTE telescope. MMJ0107 is also detected in the radio (843 MHz), Herschel/SPIRE, Spitzer MIPS 24μm, all IRAC bands, Wide-field Infrared Survey Explorer, and near-infrared (J, H, KS). We find an optical (U, B, V) source, which might be the lensing object, at a distance of″.1 from near-infrared and IRAC sources. Photometric redshift estimates for the SMG using representative spectral energy distribution templates show the redshifts of 1.4–3.9. We estimate total far-infrared luminosity of (0.3–2.2) × 10¹⁴ μ⁻¹ L๏ and a star formation rate of 5600–39,000 μ⁻¹ M๏ yr⁻¹, where μ is the gravitational magnification factor. This apparent extreme star formation activity is likely explained by a highly magnified gravitational lens system.